Photographic stencil negatives or positives



June 28,1960 7 A. E. CHARLTON 2,942,972

PHOBOGRAFHIC s'rsucn nscmzvas OR posmvss Filed Jan. 6, 1954 2 Sheets-Sheet 1 I/ II IN VEN TOR. ALEXANDER E. CHARLTON BY DES JARDINS, ROBINSON & KEISER H ls ATTORNEYS United States Patent PHOTOGRAPHIC STENCIL NEGATIVES 0R POSITIVES Alexander E. Charlton, Cincinnati, Ohio, assignor to Photoceramics, Inc., Cincinnati, Ohio, a corporation of Ohio Filed Jan. 6, 1954, Ser. No. 402,570

6 Claims. (Cl. 96-27) 'Ihis'invention relates to photographic stencil negatives or positives, and their manufacture for light printing objects with decorative designs or images, and more particularly to such stencils which are permanently flexible, extensible and pliable to be used in that form or are rigiditied in conformity with the objects, or portions thereof, to be decorated. The design or image on the stencils is formed in a dyed or pigmented mateiral, which is of the same general physical character as to flexibility, pliability or extensibility as the stencil base on which the dyed or pigmented material is applied and integrated, thereby permitting said stencils to be deformed in conformity to curved or irregular surfaces of the objects to be decorated' The stencils may, of course, be rigid or, if flexible and pliable, may be rigidified to be retained in any desired deformed shape for repeated use.

The designs or images are applied to the stencil base by means of a conventional photographic positive or negative to be in sharp and defined outline without appreciable bleeding or diffusion into the base or the resist portion during the manufacture of said stencil.

The base of the stencil to which the design or image is applied is transparent and one having excellent light transmission characteristics and with the dyed or pigmented material of the same character as the base and preferably of the same composition, the dyed or pigmented material being integrated with said base but without diffusion therethrough in order that the design or image will be entirely confined within said dyed or pigmented material.

' Heretofore, stencils have been made with dyed material of a character, or applied to the base in such a way, that the dye in the dyed material will diffuse into the resist portions and the base during, or subsequently to, the manufacture of the stencil, thereby impairing the distinctiveness of the design and shortening the useful life of the stencil. I

Accordingly, one of the main objects of the present invention is a stencil provided with a design which will not appreciably bleed or diffuse from the dyed or pigmented material.

Another object of the invention is a stencil having a transparent base with the dyed or pigmented material integrated therewith but without bleeding or diffusion of the color into the base.

Another object of the invention is a stencil which is flexible, extensible and pliable to be readily conformed to the surface of the object on which it is utilized.

Another object of the invention is a flexible, extensible or pliable stencil which can be readily deformed in conformity with the surface on which it isutilized, and then can be rigidified and retained in its deformed shape. Still another object of the invention is an apparatus adapted to use the flexible, pliable and extensible stencil for photographically reproducing the design or for deforming said stencil to irregular shape and rigidified.

Still another object of the invention is an apparatus 2,942,972 Patented June 28, 1960 paratus for utilizing the stencil for reproducing the design or round objects, such as a goblet. The rubber is of a semi-opaque nature and offers definite barriers to the transmission of light, thereby requiring a very long exposure time, and consequently unsuited for economical mass production techniques. The dye bleeds and diffuses into the undecorated portions of the rubber so as to make it unfit for use as a photographic negative or positive shortly after its manufacture.

Further objects, and objects relating to details of construction and economics of operation, will readily appear from the detailed description to follow. In one instance, I have accomplished the objects of my invention by the devices and means set forth in the following specification. My invention is clearly defined and pointed out in the appended claims. A structure constituting a preferred embodiment of my invention is illustrated in the accompanying drawings forming a part of this specification, in which:

Fig. 1 is a cross-section on an exaggerated scale of a base having a light sensitized layer in which photographic resists are formed for the design.

Fig. 2 is a similar cross-section with the resists between non-resist portions.

Fig. 3 is a similar cross-section with non-resist portions I with the resists removed, leaving the dyed or pigmented. material in the design formed by filling the spaces between.

said resists.

Fig. 7 is a top plan view of a device for reproducing a. design or image photographically from the stencil upon an object to be decorated using the flexible stencil of this invention or a conventional photographic positive or.

negative.

Fig. 8 is a vertical cross section on line 8-8 of Fig. 7 with a photographic stencil of the subject of the invention positioned in the cover, and the object to be decorated supported on a mold or jig.

Fig. 9 is a vertical cross-section similar to Fig. 8 with the flexible stencil in contact with the object.

Fig. 10 is a vertical cross-section similar to Fig. 9

using a conventional photographic positive or negative with a transparent flexible undesigned diaphragm.

Referring specifically to the drawings in which like I numerals refer to like parts, numeral 3 is a clear transparent flexible, extensible and pliable plas ic sheeting of about .002 .to .006 inch thickness, or of a clear transparent rigid plastic sheeting of about ,4 inch in thickness. It can be made of cellulose compounds or synthetic resins, many of which are suitable. Suitable eellulose compounds are cellulose nitrate, cellulose acetate,

cellulose acetate butyrate, ethyl cellulose, and the like.

Suitable synthetic resins include the acrylic, phenolic, styrene, urea, aldehyde and vinyl types, as well as manyv acrylate of about inch thickness, obtainable Comrner cially under the trade-name Lucite or Plexiglas.

A light sensitive resist layer 2 is applied to one side 7 of the :base 3. Resist materials of a suitable character for this purpose are well known and may be of any type suitable for etching resists as used in the photo mechanical industries. A preferred resist material is a bichromated glue solution which is made up as tollows:

Solution A: Ounces Distilled water 20 Photoengraving glue 6 Solution B:

Distilled water 8 Ammonium bichromate 1 The two solutions A and B are mixed separately and then combined, the mixture being first stirred thoroughly and then filtered for application to the base 3 as the resist layer 2. It may be applied to the surface of the plastic base 3 in any suitable way, preferably by whirling? Since the plastic base 3 will deform under the influence of heat, a very thin solution of the aqueous bichromating glue mixture is used to provide for easy distribution and rapid drying in the whirler in the absence of heat. Any light sensitive material can be used, the invention not being limited to any particular one. 1

Most plastics are provided with a thin greasy film surface adhering to them, and this greasy film surface is removed to enable the aqueous bichromated glue solution to be securely adhered to the plastic base. The

greasy film can be removed by vigorously scrubbing. the

surface of the plastic 3 with a water-pumice powder paste to which is added a small quantity. of an aqueous bichromate solution. The bichromate solution in the waterpumice powder paste insures better adhesiveness of the bichromate glue solution to the plastic to form the layer 2.

A conventional half-tone or line positive or negative 4 (Fig. 1') is applied in abutting relationship over the bichromated glue layer 2, this having, opaque portions 5 and transparent portions 6. The whole structure is then exposed to an actinic light source, the exposure pref erably being made in a vacuum frame. To avoid hala'tion or objectionable spreading of the light beyond the exposed areas of the light sensitive layer 2 immediately beneath the transparent portion 6, the underside of the transparent plastic 3 is backed with black paper or other materials (not shown) of a light absorbing character. The actinic light coming through the transparent portions 6' of the negative or' positive 4 (Fig. 2) will substantially harden and render water-insoluble the light exposed portions 8 of the light sensitive layer 2 which are directly underneath the transparent portions 6 of the negative or positive. The non-exposed'li'ght portions 9 of the light sensitive layer arc-not hardened but remain water-soluble, and they are removed by being washed with water, preferably at a temperature of about 70 R, leaving only the hardened Water-insoluble portions 8, which have been exposed to the light, adhered to the base 3 as shown in Fig; -3-with the intervening spaces 10 resulting from the removed water-soluble and non-exposed light portions 9;

In order to give visibility to the operator or'for better judging the degree of development, the design or image may vbedyed'with any suitable dye solution, such as an aqueous nigrosine-dyesolution flowed over the design or image- The design or image'is preferably further hardcued by being treatedlwith any suitablehardening agent,

such as being immersed in a fifteen percent formaldehyde solution, a ten (10%) percent chromic acid solution, or any other suitable hardening agent.

After the design or image is hardened and dried, it is then covered with a light absorbing or light obstructive dyed or pigmented resinous material and plasticizer 11 dissolved in :a solvent carrying Vehicle and applied in any suitable manner, such as by spraying. The resist portions 8 are covered and the intervening spaces 10 are filled with a dyed or pigmented plasticized material, there being a substantial thickness of the material 11 to insure the spaces between the resists being completely filled V with said dyed or pigmented plasticized material.

When utilizing a light obstructive dye, any dyed resin ons plasticized material is suitable that is compatible with a solvent or combination of solvents which will merely soften the exposed portion of the base layer 3 for surface penetration to make a coalesced bond therewith but will not diffuse, therethrough. To eifectively obtain this result, dyed resinous plasticized materials are selected which are soluble in a solvent that is non-compatible with the base, and then incorporating therewith a limited amount or solvent which is compatible with the base material 3 and the dyed resinous plasticized material 11, or is known to have dissolving tendencies therefor. In this manner, the penetrating action of the dye solution upon the base material can be easily controlled by increasing or decreasing the amount of compatible or penetrating solvent or solvents in the dye solution. Penetration of the dye solution, its plasticizer or solvent into the base is held to a minimum so that there will not be objectionable bleeding or diffusion of the dyed material into the base material 3, but it will be welded or coalesced therewith to prevent removal thereof in later processing the stencil. It will also facilitate the subsequent removal of the resists without impairing the bonded dyed material. The purpose of the resin, plasticizer and solvent in the dye solution is so that the resulting image is an inte-' grated part of and of a similar character to the base in respect to flexibility, pliability and extensibility. The resin and plasticizer for the dye are preferably of the same composition as that of the base on which they are applied so that they will be welded or coalesced into a cohesive integrated structure as distinct from being merely adhered, the proportion of; the compatible solvent for the base being merely suflicient to effect local coalescence without penetration through the base. A- pigment can be used in lieu of the dye, audit will prevent bleeding of the colored material. V

The plasticizers for the dyed resin are, in its simplest terms, those high boiling organic solvents which impart permanent flexibility to otherwise rigid plastic materials, possess solvent p'ow er to-insure their compatibility with the resin and are high boiling to insure their permanence in the plastic. The plastic material for the dye may be any of the materials used for the base 3. The penetrating action of thedye solution can be controlled simply by increasing or decreasing the amount of compatible or pene trating, solvent in the dye solution. Penetration ofthe base is held to a minimum as too much softening of the base causes the dye to diffuse into said base and under the resist portions so. that the design will not be in sharp outline. Any of the conventional commercial solvents for resins may be used.

One embodiment ofa dye solution having. the above desired qualities and suitable for application on the base member is as follows:

Geori 40011- grams 5 Grasol Blue R, Red GBN" and Yellow R are toluene soluble dyes manufactured by Geigy Company.

Santicizer 160 is a butyl benzyl phthalate plasticizer manufactured by the Monsanto Chemical Company and Geon 400 x 65 is a polyvinyl chloride resin manufactured by the B. F. Goodrich Chemical Company. The plasticizer and resin are thoroughly dissolved in the mesityl oxide, and the dyes in the order of the above listing are dissolved in toluene. Then the two mixtures are combined. In the above example, the toluene is the solvent for the dyes and the mesityl oxide is the penetrating solvent for the base. This solution will produce a black, light-obstructive image when applied on the base member over the resists as shown in Fig. 4.

For application of the dye to a rigid Lucite or Plexiglas base, 3 grams of a polymerized methacrylate powder are dissolved in 35 cc. of methyl ethyl ketone and then incorporated with the quantities of toluene and dye in the above specified proportions for the flexible base. The plasticizer is omitted for application to the rigid Lucite or Plexiglas. This will also produce a black, light-obstructive image when applied upon the rigid base. By using 15 grams of Grasol Red GBN and eliminating the Grasol Blue R, and Grasol Yellow R, from the two above examples, a red light absorbing image is formed. The dye solution may be applied inany suitable manner such as by spraying. The dye solution is applied to cover the design and fill the intervening spaces. It will penetrate into the base member for a substantial depth, as shown at 15, in a localized surface area to provide a secure coalesced bond therewith.

As pointed out above, the degree of penetration of the dyed material into the base is controlled so that an effective bond is obtained without diffusion of the dye through the base, particularly immediately under and into the.

resists. This permits the subsequent removal of the resists without impairment of the afiixed dyedmaterial, and retains the dyed material in sharp contrast with the base.

It will, of course, be understood that the above examples of the dye solutions are for illustration only and that other dyes, plastics, and solvents may be used. The invention is not limited to any of the particular materials used.

After the dye coating as applied in Fig. 4 has dried, its surface is then treated with a mild solvent to remove that portion which is superimposed on the resists, leaving said resist portions and the spaces therebetween filled with the dye material and its top surfaces 17 being flush with the top surfaces 18 of the resists as shown in Fig. 5. The solvent used for this purpose should be one which has very little afiinity for the plastic base 3, the dyed material or any of the components of the dyed material. It should also possess very little solvent action for any of these materials, and vigorous rubbing is neces sary to remove the areas of the dyed layer from above the resist portions. For the above types of dyes, sol vents, plasticizers and base materials turpentine is satisfactory for this removal operation, it being applied with absorbent cottonvigorously rubbed over the surface, care being taken to rub evenly over the whole surface of the image or design to remove the dye material down to the top surface of the resist portions as shown in Fig. 5.

The structure, as shown in Fig. 5, is dried and then introduced into an oven or under infrared lights, at a temperature not exceeding that which would deform the plastic, for several hours. Ordinarily. most plastics begin to soften and deform at temperatures exceeding 150 F., and, therefore, the heating temperatures should not be in excess of 150 F. This heating operation serves to volatilize and remove the solvents present in the various coatings and in the base. Thereafter, the stencil areas or resists are removed by scrubbing with a stiff brush and pumice powder to produce the finished nega- The process above described can be used for reproducing photographs and images upon plastic articles in various colors, using dyes or pigments other than light absorbing and light obstructive. By selectively spraying or coating different areas or portions of the resists with different colored dyes or pigments, multicolor reproduc-' tions are made possible. The stencil can also be used as a photographic negative or positive for photographic decoration of articles to be decorated, said stencil being sufiiciently pliable and extensible to adapt itself to any contour of the articles to be decorated whether they be fiat or irregular. Or, as above described, the base may be normally rigid, but, whatever the character of the base, the dyed or pigmented design thereon will be of the same or similar character and integrated therewith Without diffusion therethrough.

The stencil above described, whether flexible or rigid, is suitable as a contact negative or positive for photographically decorating objects by conventional methods, or by the method disclosed in my application Serial No. 337,500, now Patent No. 2,990,255, which is incorporated in full herein by reference as a part of the disclosure of this invention. The pliable extensible stencil is adapted to be deformed into close contact with the irregular surface of each object to be decorated, or, it may be deformed in conformity with a particular irregular surface, and then rigidified in that deformed condition for repeated use in decorating identical objects having the same surface irregularity. It will also be understood that the stencil can be laid flat upon a flat object to be decorated, or that it may also be stretched flat.

The apparatus shown in Figs. 7, 8 and 9 is suitable for repeatedly using the flexible stencil for decorating objects of different irregularity or for deforming the stencil to a particular irregularity to be rigidified for repeated use in its rigidified deformed condition. Fig. 10 illustrates using a transparent or light transmitting plastic sheet in association with a conventional photographic positive or negative.

surfaces but cannot be used on unevenly or compounded curved surfaces where they need to be stretched to conform thereto.

Numeral 25 (Figs. 7 to 9) designates a box-like structure having an interior chamber 26 enclosed by the bottom wall 27, sidewalls 28 and a cover 29 hinged to the box at 30. The cover is provided with a circular opening 31 over which the negative or positive stencil 24 is spanned and secured as hereinafter described. The cover is made air tight with the box by a rubberized gasket 32 inserted between the cover and top edge of the surrounding wall of the box to be compressed therebetween when the cover is tightly closed on the box by locking clips 33. A nozzle 34 is fitted to the wall for being connected to a suction device so that the air may be Withdrawn from the chamber when the cover to the device is closed.

The stencil 24 is clamped to the cover over the opening'31 by means of clamp bolts 35 projecting therethrough and through the cover 29. The marginal edge of the stencil 24 is interposed between two non-metal gaskets 36 and 37, such as rubber, and these two gaskets are interposed between the margin of the cover 29, sur rounding the opening, and a metal ring 39. 40, such as a dinner plate, to be decorated is placed in the box with its bottom side seated against the top surface 41 of a mold 42 that is shaped generally in conformity with the contour of the bottom side of said dinner plate. The mold is provided with a series of ver- Conventional photographic positives and negatives can be used on flat or evenly curved The object "th e eih n i he es e t i with he l h obstruction thereon to be stretched and flexed into close contact the :light sensitive coating 45 on the object is be dee re eie h r 11 s the es e h iee y reproduced on the dinner plate by light exposure through said photographic stencil. When the vacuum is broken, e ,n etes anhie etehe 1991 3? t it e s hh p 11 ast .me e iei when t teh d. w l n l eee' e v hsl the e e v ie lhw s en el ing. However, any resulting sag of flexible photo;

r h teheile h to e -e eh h is he i t he ne i ,ie etet t he i in th e a e e hsh r h 93 th e h eh e t e a t 'b decorated, and it is h tha s et d P s n he reproduction is made. Accordingly, any substantial recovery following a stretching operation is wholly imn aterial, it being snfiicient that the recovery is enough to cause the restietched stencil to be taut and free from nkles V H. H "I eu 'e es te eh hs e s e i t h een e m y of the contour of the neat objects to be decorated, partiehlerly i he ne t hieete to be d ee d a he sh n or duplicates of the first one, the deformed or restretched e e e h h is e'h es n he st t hed ei ie by s an a ent thee ihs ap ied o h ld th et e l in its deformed condition. can be done by applyiiig a transparent plastic. in fluid condition on the tops uraeeef the ph t r phic e e eil and a lo i e Pla t te eel sh' y ahd'h behde t ihe et hei Th en-a1 an en e s b e nt seed by simpl fit i it ag'aiiiet h the ieet 9 be d el' ed wh eh is Qf't e sam c intour as the first decorated one for the reproduction to be made by exposure of light through the transparent backns 9f the n hh ed ei nised .etehe l The t p ren l hin ea h n ieh 1, th flex tencil in s y emaeu he the sh arin h heh h er h k M I h able material is satisfactory, such as a resin which has a seed lig t h h hiiee eh tendehe nd-i e' i iiml min t th .dieeq er hseheet 9f sh ev le light? T resin should contain siifiicient solvent for securing it to the reproducing stencil, and the solvent asv/ell as any diluents contained therein, should be quick drying. The reproducing 'stenoii is held deformed until the backing dries into solidified form, and drying can be accelerated by heating. Afteroomplete drying, the vacuum, is broken to release thereproducing stencil in its deformed condition for repeated use on like articles to be decorated. Methyl rnethacrylate resin is suitable for backing a poly; vinyl reproducing stencil.

7 It will also be understood that the flexible, expansible reproducing'stencil can be stretched radially ma plane or flat condition as Well as being deformed at an angle to its plane. However, in whatever direction or dir'ections the stencil isstretched, the stretch is uniform so that there is no undue distortion of the design. The design may, therefore be in suiiiciently small size on the stencil to compensate for a larger design to be obtained from subsequentstretching of said stencil for making the reproduction, thereby being particularly adapted for making enlarged reproductions.

It will also be understood that'nor'mally rigid reproducing stencils can be stretched or deformed by heating, and that such are included in referring to the reproducing 8 sheet as being flexible, pliable and extensible. They can be inherently'of that character or so treated to have that character. i

In the embodiment of Fig. 10, the flexible member 46 is not a photographic stencil of the: subject invention but is a transparent light transmittingmembr having all the physical characteristics of said photographic stencils,

but not imaged, to be used in connection with said stencil.

or with a conventional photographic positive or negativ'e 4 7. This member 47 can be a part of member 46 or can be positioned separately upon the dinner plate 40, that is over the light sensitive coating 45 on said dinner plate. Air is then evacuated from the chamber the same as described in reference to Figs. 7 to 9 where the stencil is mounted in thecover of the apparatus. in this embodiment the flexible member 45 is simply serving to be cornpressed against the member 47 for insuring close contact thereof with the sensitized surface of the object which is being decorated.

I am' aware that there may be various changes in details of construction in respect to the flexible photographicplate and the devicein which said plate is used Without departing from the spirit of my invention, and, therefore, I claimmy invention broadly a-s'indicated by the appended claims.

Having thus described'my invention, what I claim as new and useful and desire to secure by US. Letters Patent, is: 5

'1. The method of making a photographic stencil comprising a normally deformable base .with a normally deformable stencil design coalesced therewith, deforming the base and stencil design to a surface to be decorated; and then rigidifying said' base and stencil design in their deformed condition by applying a rigid'backing to one side of the stencil in conformity with its deformed condition.

2. The method of claim -1 in which the rigid backing applied to the base and stencil design is transparent -3. The method of photographically decoratingobjects comprising placing the object to be decorated in an enclosure having one transparent flexible wall, applying a film coating of light sensitive material to the object next adjacent the flexible wall, overlaying the film coating with a photographic stencil, evacuating air from the enclosure to cause the flexible wall to draw the stencil into close contact with the film coating, and exposing the stencil to light for forming the stencil design in the :light sensitive material.

4. The method of claim -3 in which the stencil forms the flexible w all of the enclosure.

5. The method of photographically decorating objects of irregular surface contour comprising forming a flexible transparent photographic stencil, coating the irregular surface of the object with light sensitive material, compressing the stencil over the coated surface of the object in conformity with its irregular surface, and permanently rigidifying the stencil in its deformed condition. ,7 4 6. The method of claim 5 in which the stencil 1s r1g1d1- fied by molding a transparent rigid backing upon the I deformed stencil.

References Cited in the file of this patent UNITED STATES PATENTS 

3. THE METHOD OF PHOTOGRAPHICALLY DECORATING OBJECTS COMPRISING PLACING THE OBJECT TO BE DECORATED IN AN ENCLOSURE HAVING ONE TRANSPARENT FLEXIBLE WALL, APPLYING A FILM COATING OF LIGHT SENSITIVE MATERIAL TO THE OBJECT NEXT ADJACENT THE FLEXIBLE WALL, OVERLAYING THE FILM COATING WITH A PHOTOGRAPHIC STENCIL, EVACUATING AIR FROM THE ENCLOSURE TO CAUSE THE FLEXIBLE WALL TO DRAW THE STENCIL INTO CLOSE CONTACT WITH THE FILM COATING, AND EXPOSING THE STENCIL TO LIGHT FOR FORMING THE STENCIL DESIGN IN THE LIGHT SENSITIVE MATERIAL. 